Electromechanical Brake Caliper With Elastic Piston Vibration Isolation

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Solution Overview

Problem

Vibrations in rotary shafts cause wear and loss of braking force in electrical disc brake systems due to vibration transfer through motor and gear transmission, leading to shifting gears and reduced braking efficiency.

Innovation Solution

An electromechanical screw jack with an elastically compressible piston assembly, utilizing a cup spring pack to absorb vibrations and maintain constant clamping force, combined with a gear transmission and sensors for monitoring and control of braking force.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If electrical power is used to replace hydraulic power in disc brakes, then the risk of hydraulic fluid leakage is eliminated, but vibrations from the rotary shaft are transferred to the motor and gear transmission causing wear and loss of braking force

Engineering Contradiction:
Improveelimination of hydraulic fluid leakage riskVSAvoidvibration transfer to motor and gear transmission
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent introduces an intermediate element (elastic element or resilient mounting) between the brake pads and the motor-gear transmission system. This intermediary component absorbs and isolates vibrations from the rotary shaft, preventing them from being transmitted to the motor and gear transmission, thereby protecting these components from wear and positional shifts while maintaining the reliability benefits of electrical power actuation

Inventive Principle:
Principle #24Intermediary (Mediator)

2Force

If rigid connection is used between brake pads and motor transmission, then precise force transmission is achieved, but vibrations cause gear position shifts and loss of braking force

Engineering Contradiction:
Improvebraking force transmissionVSAvoidgear position stability
Core Design Contradiction:
ForceVSStability of the object's composition

Solution Approach 1:

The patent employs dynamic elements (elastic components, compliant mechanisms) in the connection between the brake pads and motor transmission. These dynamic elements allow the system to adapt to vibrations by deforming elastically, maintaining stable gear positions while still transmitting the necessary braking force. The system transitions from a static rigid connection to a dynamic compliant connection that can absorb disturbances

Inventive Principle:
Principle #15Dynamics

3Volume of moving object

If motor size is reduced to achieve compact design, then installation space is reduced, but clamping force capability is limited

Engineering Contradiction:
Improvemotor sizeVSAvoidclamping force
Core Design Contradiction:
Volume of moving objectVSForce

Solution Approach 1:

The patent replaces a direct mechanical connection system with an electromechanical screw jack mechanism. This substitution allows a smaller motor to generate the required clamping force through mechanical advantage provided by the screw jack, which converts rotational motion into linear motion with force multiplication. The cup spring pack further enhances this by providing elastic energy storage and force amplification, enabling compact motor design while maintaining high clamping force capability

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Effectively isolates motor and gear transmission from rotor vibrations, ensuring continuous clamping force and compensating for brake pad wear, while allowing for high clamping forces with moderate motor size and power, and preventing hydraulic fluid leaks.

Implementation Method 1

vibrations in a rotary shaft will to the widest extent be absorbed by the piston assembly

Methodology Applied
Scientific EffectVibration absorption: Vibration

Implementation Method 2

an elastically compressible piston assembly that is disposed to operate between a jack screw and a piston

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 3

the actuator is realized in the form of an electromechanical screw jack

Methodology Applied
Scientific EffectElectromechanical energy conversion:

Implementation Method 4

an electrical motor activates the brake via a worm gear transmission including a planetary roller screw that drives a spindle in axial translation

Methodology Applied
Scientific EffectMechanical energy transformation:

Data Source

PatentEP3244084B1Braking device for a rotary shaft or running rail
Publication Date: 2021.04.14 DELLNER BRAKES AB
  • EP3244084B1 patent drawingFigure 1
  • EP3244084B1 patent drawingFigure 2
  • EP3244084B1 patent drawingFigure 3

AI summary

A braking device for a rotary shaft or rail is disclosed, the braking device comprising a bracket (1) in which a brake caliper (2) is suspended floating on guide pins (3,4), first and second brake pads (8,9) supported in the brake caliper movable between braking and idle positions, an actuator applying a pressure for moving the brake pads towards each other in braking mode, and return springs (5,13) in non-braking mode effective for returning the brake pads to idle positions. The actuator is an electromechanical screw jack (15) that acts upon one of the brake pads (9) via an extendable piston assembly (16) that is elastically compressible in the extension direction (E).